Egyptian Journal of Biomedical Engineering and BiophysicsEgyptian Journal of Biomedical Engineering and Biophysicshttps://ejbbe.journals.ekb.eg/
Tue, 20 Nov 2018 03:14:15 +0100FeedCreatorEgyptian Journal of Biomedical Engineering and Biophysicshttps://ejbbe.journals.ekb.eg/
Feed provided by Egyptian Journal of Biomedical Engineering and Biophysics. Click to visit.In vitro Study of Novel Organic/ Inorganic Composite Scaffold for Bone Regenerationhttps://ejbbe.journals.ekb.eg/article_4719_1712.html
In this study, polysaccharide polymers /Hydroxyapatite composite scaffolds were prepared by using freeze-drier processing technique. The microstructure and morphology as well as mechanical strength of the scaffolds were characterized by XRD, FTIR, SEM, EDX, and other methods. The porosity ratio and in vitro biomineralization of the scaffold were also evaluated. It was found that, both porosity and compressive strength are strongly dependent on the concentration of HA. The porosity was reduced from &asymp; 87 &plusmn;5.1% to 66.7&plusmn;3.2%, while the mechanical measurements revealed that, the compressive strength reaches the highest value 23.96&plusmn;0.82 MPa by adding HA to hybrid polymers. In addition, Blended hydroxyethylcellulose to sodium alginate cause increase of total pore volume inside scaffold, decrease in mechanical properties and the presence of bioceramic inside scaffolds structure enhances the precipitation and biomineralization of HA from SBF on scaffolds surface. Thus results suggest that these biocompatible composite scaffolds can be useful for bone tissue regeneration.Thu, 30 Nov 2017 20:30:00 +0100The Dielectric Study of Calcium Hydroxylapatite Doped by Magnesium Ionshttps://ejbbe.journals.ekb.eg/article_14445_0.html
Hydroxyapatite is considered as one of the most effective biomaterials with general formula Ca10 [PO4]6[0H] 2 , many substances have been used for doping hydroxypatite like F, Mg, CO3, Zn, Bi and Na ,to improve the properties of the HA crystal . In this paper, we discuss the influence of magnesium ions on the electrical properties of the HA crystal . HA (S1) and Mg loaded hydroxy apatite (S2,S3 and S4) of different magnesium concentrations have been prepared by wet precipitation method. The dielectric parameters (&epsilon;' ) and (&epsilon;'') measured at different temperature, relaxation time of relaxation process was calculated from the cole cole plot . The advantages of modulus studies were to recognize the conduction process and study the effect on the frequency and estimate the relaxation frequency. Conduction mechanism has been studied using alternating current measurements, analyzing their dependence on temperature and frequency. The exponent (S) was estimated to recognize the type of conduction. The activation energy studied also to confirm the conductivity measurements . The electrical measurements confirmed that as the addition of Mg increased , the conductivity of the substance would increase and this will improve the bioactivity of HA .Sat, 22 Sep 2018 20:30:00 +0100Controlling the Features of Electrospun Nanofibershttps://ejbbe.journals.ekb.eg/article_6325_1712.html
The major challenge of the electrospinning process lies in the optimization of its parameters to achieve desirable nanofibers morphology and properties. The present work highlights the change of properties for electrospun poly ɛ-caprolactone and poly ethylene oxide with modulation of different parameters. The effect of solution parameters such as; concentration poly ɛ-caprolactone, concentration of poly ethylene oxide relative to poly ɛ-caprolactone, viscosity , different solvents, voltage properties and distance separates tip of the syringe and collector to fabricate poly ɛ-caprolactone electrospun nanofibers with desired morphologies is indicated in present work. Morphologies of the processed nanofibers are examined by FESEM, the average diameter of nanofibers and their normal distribution are investigated by image j analyzer software. Of all combinations, the best and the finest nanofibers are obtained at 10%wv poly ɛ-caprolactone, 3% wv poly ethylene oxide concentration with respect to that of poly ɛ-caprolactone, at voltage 20 kV and lastly at 12 cm distance separates the tip of syringe and collector.Thu, 30 Nov 2017 20:30:00 +0100Validation of the Octavius 4D Measuring System in Verifying Advanced External Beams ...https://ejbbe.journals.ekb.eg/article_6326_1712.html
The development of advanced techniques as Intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) are characterized by their numerous steep dose gradient using the dynamic MLC modality and these requires specific quality assurance (QA) to meet this complexity. The conventional dosimetery techniques, such as ionization chamber, point dose measurements and film dosimetry, are gradually being replaced by detector arrays which can produce accurate results immediately. There are many commercial detector arrays one of them is 2D-ARRAY seven29 (PTW, Freiburg, Germany). We used the Octavius 4 D measuring system with its detector array, ionization chamber. The accuracy of the synchronizing motion of the phantom was validated. It was found that the detector array response is stable after warming up with 800 MU, the dose rate measurements and the dose response is linear with R2=0.929. The gamma index for the clinical IMRT plans were found to be 93.3%, 98.0 %, 95.5% and 96.2% for head and neck, prostate, breast and brain cases, and for VMAT plans are 96.3%, 99.4 %, 98.1% and 98.6% for head and neck, prostate, breast and brain, respectively, using gamma criteria 3%/3 mm. The aim of this work is to characterize and validate the Octavius 4D measuring system for 6MV beams. Also, to verify clinical IMRT and VMAT plans, the volumetric dose matrix of the clinical plans, dose line profiles and to study the factors affect the gamma index.Thu, 30 Nov 2017 20:30:00 +0100Influence of Nanocomposite Scaffolds Using Freeze-drying Technique on Hepg2https://ejbbe.journals.ekb.eg/article_7431_1712.html
Novel approaches are devoted towards creating 3D scaffolds that allow good permeability and diffusion. Appropriate synthetic biodegradable materials for this purpose are biopolymer- bioceramic nanocomposites. They have good tissue compatibility and safety profiles seem essential for their successful utilization in medical applications. The 3D dicalcium phosphate/dextran/ sodium carboxymethyl cellulose nanocomposites are prepared by freeze-drying method. In the present work, the physico-chemical properties of scaffolds are evaluated by XRD and FTIR. The interior morphology as well as porous structure are evaluated by scanning electron microscope (SEM). The porosity of scaffolds examined by mercury intrusion porosimetry (MIP). In addition to compressive stress parameter is also determined by Instron Industrial Product,(Model 3345;Norwood, MA, USA).The respective nanocomposite scaffolds are tested for in vitro Hepg2 cancer cytotoxicity. The nanocomposite scaffolds exhibit good biocompatibility and exerts no toxic effect on Hepg2 liver cancer cell. Therefore, the prepared porous system of nanocomposite scaffolds can be considered as promising technique for tissue engineering.Thu, 30 Nov 2017 20:30:00 +0100Efficiency of Photodynamic Therapy and Avastin in Treatment of Corneal Neovascularization in ...https://ejbbe.journals.ekb.eg/article_7432_1712.html
The aim of the present work is to evaluate the effect of photodynamic therapy (PDT) by using argon laser with rose bengal (Herbs) as a photosensitizer when compared to the Avastin for treatment of corneal neovascularization (CNV) in rabbits. Thirty-Nine New Zealand male rabbits aged 2.5 months and weighing 2.5-3 kg are selected from the animal house of research institute of ophthalmology, Giza, Egypt. Three rabbits are used as control, and 36 rabbits are subjected to corneal neovascularization (CNV) induced by 3 silk sutures at mid-stromal depth approximately 1 mm from the limbus. After four days, sutures are removed and slit lamp examinations are performed to determine the area of CNV. Rabbits with CNV are divided into 3 groups: (1) The first group left without any treatment(n=12); (2) The second group&nbsp;(n=12 rabbits)&nbsp;were generally anesthetized and&nbsp;rose bengal(C20H4Cl4I4O5)&nbsp;with a dose of 50 mg/Kg was administered by slow intravenous injection in the marginal ear vein.&nbsp;After 15 minutes, rabbit&rsquo;s eyes were exposed to&nbsp;argon&nbsp;laser(Quantel-Medical, Vitra, France)&nbsp;in a pulsed mode at 532 nm, spot size of 50 &mu;m, pulse duration of 0.2 ms and a power of 150-200 mW/cm&nbsp;2.; (3) The third group are treated with subconjunctival injection of 25 mg Avastin (n=12). The rabbits are followed up for 4 weeks and 3 rabbits are selected and sacriﬁced weekly from each group. The corneas are isolated for determination of protein content, SDS-poly acrylamide gel electrophoresis, total antioxidant capacity (TAC) and total oxidative capacity (TOC). Final results show that avastin is almost as effective as photodynamic therapy.Thu, 30 Nov 2017 20:30:00 +0100Effect of Blue and Green Light Emitting Diode (LED) on Rat's Retina.https://ejbbe.journals.ekb.eg/article_7433_1712.html
Our eyes are increasingly exposed to light from the light emitting diode (LED) of video display terminals (VDT) which contain much blue light. VDTs are equipped with televisions, personal computers, and smartphones.; hence it is so important to know the implications of LED radiations on the human visual system. The present study is designed to evaluate the influence of blue and green LEDs on rat's retina. Forty-six female Wistar albino rats weighing 250-300 g classified into 3 groups. Group (1) served as control. Group (II) exposed to (461nm) blue LED (12 hr light-dark cycle) for 3, 7, 14 and 21days. Group (III) exposed to (525.9 nm) green LED (12 hr light-dark cycle) for 3, 7, 14 and 21days. At the end of each period, electroretinogram (ERG) and microscopic examination are carried out. The results indicated that there was no significant effect for the green LED on the ERG, and microscopic examination illustrates mild changes.&nbsp; &nbsp;After exposure of rat's retina to blue LED, there is a reduction in a- and b- wave amplitudes, and the histopathological examination illustrates severe changes. The data suggest that the blue LED may cause retinal toxicity. Therefore, it is very important to recognize the hazard of LED radiations that affects vision and take appropriate precautions for the eye safetyKeywords: Light emitting diodes, Electroretinogram, histopathological examination.Thu, 30 Nov 2017 20:30:00 +0100The Role of Liposome -Encapsulated Ascorbic Acid on Hemoglobin Damage by Gamma Irraidation.https://ejbbe.journals.ekb.eg/article_7434_0.html
Ionizing radiation causes serious damage in a biological system. Some drugs and antioxidants are used to prevent such damage. In vitro we study the effect of free ascorbic acid(AA) and liposome encapsulation ascorbic acid (LEAA) to prevent damage induced by gamma irridiatin on rats blood . Liposomes prepared by thin film hydration method . Size ,and poly dispersed index (PDI) were analyzed by dynamic light scattering before and after encapsulation AA ,and shape was analyzed by transmission electron microscopy(TEM). Percentage encapsulation efficiency (EE%) of ascorbic acid was determined and IR study has been employed to reveal structure alteration in vesicles before and after encapsulation. two doses of free ascorbic acid ( 20 &micro;g /ml ,40 &micro;g /ml) were selected to be used for such purpose. Also the same doses were used encapsulated in liposomes . Our study were carried through UV-visible spectrum absorption spectrum , relative viscosity and conductivity measurement . The results show that EE% have a high encapsulation of vitamins C, there no detectable change is observed in size of liposome before and after encapsulation. The data obtained from UV-visible indicate that there is great change in the absorbance of sort band, and in the absorption A576/ A541 ratio in blood irradiated to 5 GY &gamma;- irradiation by dose rate 62cGY/mint as compared with normal hemoglobin. The result indicated that ,the change decreases by increasing doses of free AA came close to normal hemoglobin and approaching more to normal in the case of liposome encapsulation ascorbic acid .Mon, 21 May 2018 19:30:00 +0100Biophysical Studies on the Effect of Gamma Rays on Liposomeshttps://ejbbe.journals.ekb.eg/article_7435_0.html
Liposomes are vesicular structures made of lipids that are formed in aqueous solutions, which can be used as models to study the cell membrane. In the present study the effects of gamma (&gamma;) rays on dipalmitoylphosphatidylcholine (DPPC) liposomes were studied by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, as well as dynamic light scattering (DLS) and viscosity measurements. The DPPC liposomes were exposed to three different doses 40, 80, and 120Gy which emitted from 60Co gamma rays source with a dose rate of 9 kGy/h. The DLS measurements confirmed the monodispersity of all samples. TEM results revealed that there is a change in morphology and size of liposomes, which is in a good agreement with the increase in viscosity measurements. FTIR measurements showed significant changes in the characteristics bands of DPPC liposomes confirming the effect of &gamma;-rays on the main groups such as CH2 bending vibrations and the symmetric and antisymmetric PO2- stretching vibrations at 1090 and 1220 cm-1 respectively. In addition to the shifting of the OH stretching vibrations from 3439 cm-1 to 3453 cm-1due to the 120 Gy exposure. The spectral changes seem to be due to some sort of water loss and molecular conformational changes due to ionization and formation of free radicals which affect the head groups of the DPPC liposomes leading to lipid lateral diffusion enhancing the fusion of small vesicles to form larger structures.Mon, 21 May 2018 19:30:00 +0100Molecular Structure Changes Of Rat’s Retina After Sodium Iodate Injection and The Effect Of ...https://ejbbe.journals.ekb.eg/article_19571_0.html
The aim of present work is to investigate the mechanism of action of sodium iodate (NaIO3) on the molecular structure of retina and whether the nutritional intake of taurine may delay the development of age macular degeneration (AMD) disease induced by NaIO3 using Fourier transform infrared spectroscopy (FTIR). One hundred and five rats (200-230 g) are classified into three groups. I (15 rats) used as control, II (45 rats) received a single intravenous injection of 25, 50, or 75 mg/kg NaIO3, and III (45 rats) supplemented with 4 g taurine /100 g diet for two weeks before injection of NaIO3. The injection continued until decapitation. All injected doses of NaIO3 are associated with vibrational changes that include decrement of the modes of vibration related to stretching OH and amide II, significant increases (p˂0.05) in wavenumber and width of asymmetrical OH and disappear of asymmetrical NH3. Also, there are significant diminish (p˂0.05) in &alpha;-helix content in the same context, in addition to significant increments (p˂0.05) in &beta;-Sheet indicating the conformational changes of the secondary structure of protein due to NaIO3 injection. Enhancement of most changes that previously detected in FTIR spectra are noticed after taurine treatment especially before and after low dose of NaIO3. NaIO3 is considered to be specific for animal model as age macular degeneration. Taurine action is efficient as antioxidant to protect retina from oxidative stress limits in range of 25 mg of NaIO3 and decreases the efficiency by increasing the dose of NaIO3 up to 75 mg.Sun, 18 Nov 2018 20:30:00 +0100